What Is a Board Foot?
A board foot (BF) is the standard volume unit for pricing hardwood lumber in North America. One board foot equals a piece of wood 1 inch thick, 12 inches wide, and 12 inches long — that is 144 cubic inches. The formula is straightforward: BF = (thickness in inches × width in inches × length in feet) ÷ 12. For a 1×6 board 8 feet long, that is (1 × 6 × 8) ÷ 12 = 4 board feet.
Quarter-Inch Thickness Notation
Hardwood thickness is written in quarters of an inch because that is how the mill measures rough lumber before it is planed. "4/4" (four quarter) is 1 inch, 5/4 is 1.25 inches, 6/4 is 1.5 inches, 8/4 is 2 inches, and so on up to 16/4 (4 inches). When you see a price list showing "Walnut 4/4 $12/BF", it means 1-inch-thick rough walnut at $12 per board foot. After planing to finished thickness, 4/4 typically dresses to 13/16 inch — you paid for the sawn thickness, not the final.
Converting Board Feet to Cubic Meters
Most countries outside North America price lumber in cubic meters. The conversion is 1 BF ≈ 0.00236 m³ or equivalently 424 BF per m³. This calculator shows both values automatically so you can compare North American and European hardwood quotes on an apples-to-apples basis.
Why Board Foot Instead of Square Foot?
Square foot measures only the surface area and ignores thickness. A 4/4 board and an 8/4 board of the same face dimensions contain the same surface area but very different volumes of wood. Board feet account for all three dimensions, which is why hardwood mills use them for pricing. For sheet goods like plywood, though, square feet are more practical since sheets all come in 4/4 or 3/4 thickness.
Board Foot Quick Reference
Board feet for a single piece at standard sizes, calculated as (thickness × width × length) ÷ 12:
| Dimensions | 6 ft | 8 ft | 10 ft | 12 ft |
|---|---|---|---|---|
| 4/4 × 4" (1×4) | 2.0 BF | 2.67 BF | 3.33 BF | 4.0 BF |
| 4/4 × 6" (1×6) | 3.0 | 4.0 | 5.0 | 6.0 |
| 4/4 × 8" (1×8) | 4.0 | 5.33 | 6.67 | 8.0 |
| 4/4 × 12" (1×12) | 6.0 | 8.0 | 10.0 | 12.0 |
| 8/4 × 6" (2×6) | 6.0 | 8.0 | 10.0 | 12.0 |
| 8/4 × 8" (2×8) | 8.0 | 10.67 | 13.33 | 16.0 |
| 8/4 × 12" (2×12) | 12.0 | 16.0 | 20.0 | 24.0 |
Typical hardwood prices (2024 US wholesale): Red oak 4/4 $5-8/BF, white oak 4/4 $7-12/BF, hard maple 4/4 $6-10/BF, walnut 4/4 $10-18/BF, cherry 4/4 $7-12/BF. Exotic species (teak, ipe, padauk) run $15-40+ per BF. Prices rise 20-40% for 8/4 stock and 50-100% for wider boards (10"+).
Frequently Asked Questions
Is a 2x4 one board foot per foot?
A 2×4 is 0.667 BF per linear foot ((2 × 4 × 1) / 12), or 5.33 BF for an 8-foot 2×4.
How many board feet in a pallet of hardwood?
A standard hardwood lift typically holds 500-1,000 BF depending on thickness and species density.
Why is hardwood more expensive than softwood?
Hardwoods grow slowly, the logs yield less usable lumber after drying and grading, and the wood is harder to work — all of which raise the price per BF.
How do I calculate BF for a live-edge slab?
Measure the average width (narrow + wide ends ÷ 2), multiply by thickness and length, divide by 12. Add 10-15% to cover the irregular edge.
Should I buy rough or S4S lumber?
Rough lumber is priced lower per BF but requires a planer and jointer to flatten. S4S (surfaced four sides) is ready to cut but costs 30-50% more per BF.
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